Question about Vortex Viper on AR

[grimreefer]

I just bought a Vortex Viper 3-9x40. Just wondering what others are doing for mounting on an AR? Rings or cantilever mount? I'm thinking a cantilevered mount is more appropriate for needed 3.5" eye relief?

 

[m39a2]

The biggest problem I see with people mounting optics on AR's is the fact they generally mount them too low and too far to the rear. A cantilever mount, setting the rear objective of the optic right about where the rear sight would be is just about perfect.

Scott